Door stops are devices used to hold a door open or closed. There are several types of door stops including attachable and stand-alone ones.
Attachable door stop devices are mounted or otherwise affixed to a wall, floor or door. One example of an attachable door stop is a stopping mechanism, usually a short metal bar capped with rubber or other high friction material and attached to a hinge.
When the door is to be kept open, the bar is swung down so that the rubber end touches the floor. However, the hinge is permanently mounted on the door. If the door is an exterior door and the door stop is used to keep the door open, the exterior surface of the door (i.e., the face) will have a door stop mounted thereon. If the face is a decorative face, a door stop may give the door an undesirable look.
Stand-alone door stop devices may be as primitive as a rock or a brick. Generally, stand-alone door stops are preferred as they are easy to install and relatively inexpensive. To hold a door open or closed, it can be as easy as placing a heavy object behind or in front of the door. These stops are predominantly improvised. Wedges made of wood, rubber, plastic and other materials are another approach to holding a door open. The wedge is kicked into position and the compressibility of the material is used to try to create enough friction to keep the door from shutting. A problem with prior art wedge designs is that if the angle of the wedge is too steep, the door will push the wedge out of the way due to the hardness and/or low friction coefficient of the floor. Also, if the floor is slick or has dust or debris on it, the wedge may slide. Furthermore, these door stops must be in a certain orientation to work. Furthermore, these door stops cause damage to floor and door from the friction of insertions. Removal of same can often time split the door laminate from the door frame.
Some prior art attempts to keep doors open or closed rely on the weight of the object. The weight may damage the floor and a person may be injured by accidentally striking the object, such as with a toe.
In some settings a floor may be covered with carpet, linoleum, tile, or some other surface. In this type of setting a problem that arises is that the floor may deform. For example, plush carpet may be compressed. If a prior art wedge is used, the maximum thickness of the wedge may be small enough that the door may compress the wedge into the carpet and then pass over the wedge, rendering it useless.
In addition to keeping a door from closing, door stops are also commonly used to prevent a door from opening past a certain angle. Doors that open too wide may damage walls when a doorknob contacts the wall, or may damage the hinges by overextending their range. The most common form of door stop for this purpose is to have a device permanently mounted to either the floor, the door, or a wall so that the door or some feature on the door contacts the door stop before the door can do any damage to the door or wall. A prior art approach involves drilling a hole in the floor and setting a pin in the hole to anchor a door stop with a rubber face. When the door swings open, the door contacts the rubber face in a relatively elastic collision that absorbs some of the momentum, but the remaining inertia is transferred to the pin. Over time, the pins can break or damage the surrounding concrete or other flooring material and must be replaced. Also, the hinges may be damaged by the vibration.
Furthermore, in the case of commercial or automatic return doors, almost all of these door stops will not operate unless they are wedged into place with considerable force, further increasing the likely hood of damage to the door or floor. If the door is even slightly bumped, the door stop is unseated and will not stop the spring loaded force of the door, particularly on smooth surfaces.
Simple wedge door stops almost all use a single hardness material that makes contact with the door and the floor resulting in an approach that may be the worst of both worlds. The surface making contact with the floor is often too rigid or hard to conform to the surface of the floor and provide desirable gripping power or surface tension of softer materials. The upper side making contact with the door is generally not of a high enough hardness to facilitate effective durability of the product, resulting in a short life product that at best is challenging and limited in use. A simple wedge design such a wood block eventually turns into a sandpaper block as dirt, sand and debris particles are through friction embedded in the surface giving the erosive effect of a glacier on a mountain with a door stop against smooth floors.